<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Crypt
 * @subpackage Math
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: BigInteger.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * Support for arbitrary precision mathematics in PHP.
 *
 * Zend_Crypt_Math_BigInteger is a wrapper across three PHP extensions: bcmath, gmp
 * and big_int. Since each offer similar functionality, but availability of
 * each differs across installations of PHP, this wrapper attempts to select
 * the fastest option available and encapsulate a subset of its functionality
 * which all extensions share in common.
 *
 * This class requires one of the three extensions to be available. BCMATH
 * while the slowest, is available by default under Windows, and under Unix
 * if PHP is compiled with the flag "--enable-bcmath". GMP requires the gmp
 * library from http://www.swox.com/gmp/ and PHP compiled with the "--with-gmp"
 * flag. BIG_INT support is available from a big_int PHP library available from
 * only from PECL (a Windows port is not available).
 *
 * @category   Zend
 * @package    Zend_Crypt
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Crypt_Math_BigInteger {
	
	/**
	 * Holds an instance of one of the three arbitrary precision wrappers.
	 *
	 * @var Zend_Crypt_Math_BigInteger_Interface
	 */
	protected $_math = null;
	
	/**
	 * Constructor; a Factory which detects a suitable PHP extension for
	 * arbitrary precision math and instantiates the suitable wrapper
	 * object.
	 *
	 * @param string $extension
	 * @throws  Zend_Crypt_Math_BigInteger_Exception
	 */
	public function __construct($extension = null) {
		if ($extension !== null && ! in_array ( $extension, array ('bcmath', 'gmp', 'bigint' ) )) {
			require_once ('Zend/Crypt/Math/BigInteger/Exception.php');
			throw new Zend_Crypt_Math_BigInteger_Exception ( 'Invalid extension type; please use one of bcmath, gmp or bigint' );
		}
		$this->_loadAdapter ( $extension );
	}
	
	/**
	 * Redirect all public method calls to the wrapped extension object.
	 *
	 * @param   string $methodName
	 * @param   array $args
	 * @throws  Zend_Crypt_Math_BigInteger_Exception
	 */
	public function __call($methodName, $args) {
		if (! method_exists ( $this->_math, $methodName )) {
			require_once 'Zend/Crypt/Math/BigInteger/Exception.php';
			throw new Zend_Crypt_Math_BigInteger_Exception ( 'invalid method call: ' . get_class ( $this->_math ) . '::' . $methodName . '() does not exist' );
		}
		return call_user_func_array ( array ($this->_math, $methodName ), $args );
	}
	
	/**
	 * @param string $extension
	 * @throws  Zend_Crypt_Math_BigInteger_Exception
	 */
	protected function _loadAdapter($extension = null) {
		if ($extension === null) {
			if (extension_loaded ( 'gmp' )) {
				$extension = 'gmp';
			
		//} elseif (extension_loaded('big_int')) {
			//    $extension = 'big_int';
			} else {
				$extension = 'bcmath';
			}
		}
		if ($extension == 'gmp' && extension_loaded ( 'gmp' )) {
			require_once 'Zend/Crypt/Math/BigInteger/Gmp.php';
			$this->_math = new Zend_Crypt_Math_BigInteger_Gmp ();
		
		//} elseif($extension == 'bigint' && extension_loaded('big_int')) {
		//    require_once 'Zend/Crypt_Math/BigInteger/Bigint.php';
		//    $this->_math = new Zend_Crypt_Math_BigInteger_Bigint();
		} elseif ($extension == 'bcmath' && extension_loaded ( 'bcmath' )) {
			require_once 'Zend/Crypt/Math/BigInteger/Bcmath.php';
			$this->_math = new Zend_Crypt_Math_BigInteger_Bcmath ();
		} else {
			require_once 'Zend/Crypt/Math/BigInteger/Exception.php';
			throw new Zend_Crypt_Math_BigInteger_Exception ( $extension . ' big integer precision math support not detected' );
		}
	}

}